Brake control checking means



Aug. 24, 1937. J. c. M CUNE BRAKE CONTROL CHECKING MEANS Filed June 2, 1956 E E mm mm ww mm NEY INVENTOR .JIJSEPH BMnCUNE BY Q/i/m/ ATTOR Patented Aug. 24, 1937 UNHTE STATES PATENT FFEQE BRAKE CONTROL CHECKING MEANS Application June 2, 1936, Serial No. 83,010

18 Claims.

This invention relates to brake control checking means, that is, to means for checking or verifying the integrity of the brake control circuits for vehicles such as railway trains.

My present invention is applicable to electrically controlled brake systems similar to that shown and described in Patent No. 2,058,008, of Clyde C. Farmer, and assigned to the assignee of the present application, in which patent the 19 brake controlling electromagnets on the cars of the train are operatively unresponsive to 2. normal low checking current in the control' circuit wires extending throughout the length of the train.

In the above-mentioned patent it is necessary that the last car of the train always be one which is specially equipped with mechanism operatively responsive to the normal low checking current in the control circuit. Furthermore, un- 20 less the last car, which is specially equipped,

accompanies the locomotive or motor car, the system for checking the integrity of the brake control circuit is inoperative.

It is accordingly an object of my invention to 5 obviate the practical difficulties involved in a system such as disclosed in the above copending application, and to provide a relatively simple system for checking the integrity of the brake control circuits, in which system the locomotive or motor car may travel alone with no trailer car and in which any trailer car may be the last car in the train, without interfering with the effectiveness or operativeness of the system for checking the integrity of the brake control 33 circuit.

The above and other more specific objects of my invention which will be made apparent hereinafter are attained by an illustrative embodiment of my invention subsequently to be described and shown in the accompanying drawing wherein,

Fig. l is a simplified diagrammatic view, showing the essential elements of an electrically controlled brake system embodying my invention,

and

Fig. 2 a diagrammatic view, indicating the circuit connections established in the various operating positions of either of the brake control switches shown in Fig. 1.

Referring to Fig. of the drawing, the equipment to the left of the central broken line is carried on the motor car while the equipment to the right of the central broken line is illustrative of the equipment carried on each of the trailer 5 cars, only the equipment for one trailer car being shown since the equipment for other trailer cars is merely a repetition of that shown in Fig. 1.

The equipment shown in Fig. 1 comprises a plurality of train wires 3, 4 and 5, hereinafter designated the supply wire, the application wire and the release wire respectively, the sections of the train wires carried on the motor car and on a trailer car being suitably connected in a well known manner by connectors such as indicated at 6.

The equipment also comprises a control pipe I, which'may be the usual brake pipe, extending throughout the length of the train, the adjacent ends of the sections of the brake pipe carried on successive trailer cars being connected bysuitable flexible hose couplings 8 of well known construction, the opposite ends of the sections o-fthe brake pipe on the cars being provided in customary manner with suitable angle cocks or Valves 9 for opening or closing the brake pipe. 1

The motor car' and each of the trailer cars are severally provided with a brake cylinder l0 and a local reservoir H, an application magnet valve devicel-Z and a release magnet valve device l3 being provided for controlling the supply of fluid under pressure from the local reservoir II to the brake cylinder l0 and for releasing fluid under pressure from the brake cylinder.

A main reservoir [4 is carried on the motor car, which reservoir is charged with fluid under pressure in the usual manner from a compressor not shown, the main reservoir being connected to the brake pipe 7! through a pressure regulat-' ing or feed'valve device It of well known construction.

The local reservoirs H are charged with fluid under pressure from the brake pipe I, through a branch pipe l6 having a check valve l l therein for preventing back flow of fluid under pressure from the localreservoirs to the brake pipe.

The equipment carried on the motor car further comprises a suitable source of current, such as indicated by the battery I8, a brake switch I9 located at one end hereinafter designated the head end of the motor car, a similar brake switch l 9a located at the opposite end hereinafter desighated the rear end of the motor car, a signal equipment 2i located at the head end of the motor car, and a signal equipment 2 la located at the rear end of the motor car. The signal equipments 2| and Zia. are identical in construction and each comprises a pair of relays 22 and 23, an audible signal device, such as an annunciator 24, and a visible signal device, such as the signal lamp 25.

According to my invention, I further provide a pair of pneumatic switch devices 21 and 28, which are of identical construction and which are located, respectively, at head and rear ends of the motor car, and a pair of control switches 32 and 33 located, respectively, at head and rear ends of the motor car. I also further provide a pair of pneumatic switch devices 29 and 3| which are of identical construction and which are located, respectively, at opposite ends of each of the trailer cars.

Referring in further detail to Fig. 1, each of the magnet valve devices 12 comprises a casing having an application valve 34 contained in a chamber 35 which is in constant communication with the local reservoir I I through a pipe 36, and an electromagnet 38 effective, when energized, to so actuate the valve 34 as to unseat it from its associated valve seat against the force of a biasing spring 31 to 'open communication between the chamber 35 and a chamber 39 which is in constant communication with the brake cylinder l0 through a passage and pipe 4|.

Each of the release magnet valve devices I 3 comprises a casing having a release valve 44 contained in a chamber 45 which is constantly open to atmosphere through a port 46, and an electromagnet 41 effective, when energized, to actuate the valve 44 into seated relation on an associated valve seat to close communication between chamber 45 and a chamber 48 which is connected to the passage and pipe 4| leading to the brake cyl inder ID by a branch passage 49. When the electromagnet 41 is deenergized, the biasing spring 5! acting on the end of the fluted stem of the valve 44 yieldingly unseats the valve 44 to open communication between the brake cylinder pipe 4! through chamber 48 to the atmospheric chamber 45.

One terminal of the electromagnet 38 of each application magnet valve device I2 is connected by a wire 54 to the application wire 4 and one terminal of the electromagnet 41 of each release magnet valve device 13 is connected by a wire 55 to the release wire 5, the remaining terminals of the electromagnet windings 38 and 41 being both connected to the negative terminal of the battery is, as through a ground connection at 56.

The brake switches I9 and Hm are identical in construction and, as indicated diagrammatically in Fig. 2, may comprise a rotary drum 58 having thereon in insulated relation a stepped contact segment 59 and a plurality of stationary contact members 62, 63 and 84 which areconnected by wires 65, 66 and 61, respectively, to the positive terminal of battery N3, the release wire 5, and the application wire 4, respectively.

In the release position of the brake switch l9 or lfia the rotary drum is in such a position that the contact segment 59 does not engage any of the contact members 62, 63 and 64. When the rotary drum 58 is operatively rotated by means of the removable handle 60, to service application position, contact segment 59 engages and connects together all of the contact members 62, 63 and 64 to establish circuits for energizing all the application magnet valve devices l2 and all the release magnet valve devices l3, the circuits being traced hereinafter in detail.

In the lap position of the brake switches I9 and 59a, the rotary drum 58 is so positioned that the contact segment 59 connects only thecontact members 62 and 63, thereby establishing-circuits 'of the relay.

contact members 82a.

sure is supplied to chamber 16, the piston is actufor energizing only the release magnet valve devices l3, the circuits being hereinafter traced in detail.

As shown in Fig. 1, only one removable handle is provided, the handle being used for operating either the brake switch device l9 or the brake switch device I911. The casing of the brake switch devices I9 and la is adapted to cooperate with the handle 60 in such manner as to prevent removal of the handle 60 from the operating shaft 58 of the rotary drum 58 except when the rotary drum 58 is in the release position.

The signal equipments 2| and Zia, located at opposite ends of the motor car are not only identical in construction but are connected to the train Wires 3, 4 and 5 in identically the same manner. Only the connections for the signal equipment M will, therefore, be described in detail but it will be understood that the signal equipment Zia is likewise similarly connected.

The annunciator 24 and the signal lamp 25 of the signal equipment 21 are connected in parallel relation between the supply wire 3 and a Wire H which is connected to one of the stationary contact members of each of the relays 22 and 23, the other stationary contact members of each of the relays 22 and 23 being connected by a common wire i2 to the negative terminal of the battery I8, as through a ground connection E3. The movable contact members 22a and 23a. of the relays 22 and 23, respectively, are normally actuated out of engagement with the stationary, contact members of the corresponding relays due to the energization of the electromagnet Winding The winding of the relay 22 is constantly connected between the. application wire 4 and the negative terminal of the battery 8 at the ground connection 13. The winding of the relay 23 is constantly connected between the release wire 5 and the negative terminal of the battery l8 at the ground connection 13.

The windings of the relays 22 and 23 are so designed as to cause actuation of the movable contact members thereof out of engagement with the stationary contact members thereof When energized by a relatively low current which is insufficient to actuatively energize the electromagnets of the magnet valve devices l2 and I3 for controlling the brakes. When either of the relays 22 or 23 is deenergized, the corresponding mov" able contact members 22a, or 23a drop into contact with stationary contact members of the relay to establish the connection between the wire I! and the ground wire 12 to thereby effect operation of the annunciator 24 and illumination of the signal lamp 25.

As will be hereinafter clearly described, the circuits for energizing the relays 22 and 23 of the signal equipments 2i and Zia may be completed under the control of any of the pneumatic switch devices 21, 28, 29 and 3|.

The pneumatic switch devices 29 and 3| on the trailer cars are of any suitable construction and may comprise a casing containing a piston 15 having a chamber H5 at one side thereof for receiving fluid under pressure. and a chamber Tl at the opposite side containing a biasing spring 18 yieldingly urging the piston '15 in opposition to the force of the fluid pressure in the chamber '16, the piston 15 having a stem 19 carrying a pair of insulated contact members 8! and 82 for cooperating respectively with a pair of stationary contact members 8M and a pair of stationary When fluid under presated against the force of the spring 18 to eifect separation of the contact members SI and 82 from their respectively associated contact members 8m and 82a.

Chamber '85 of the pneumatic switch device 29 is connected to the brake pipe 1 by a branch pipe 35 which opens into the brake pipe at a point between the angle cock 9 and the hose coupling 8 at one end of the trailer car. In a similar man ner chamber 15 of the pneumatic switch device 5i is connected to the brake pipe I by a branch pipe 86 which opens into the brake pipe at a point between the angle cock 9 and hose coupling 8 at the opposite end of the trailer car.

As is well known, the angle cock at the rear end of the last car in the train is always in closed position, to close the end of the brake pipe 1, since the hose coupling 8 at the rear end of the last car in a train is vented to atmosphere. It will thus be seen that the chamber 76 of the pneumatic switch device 3| on the last trailer car is always vented to atmosphere. The contact members 81 and 82 of the pneumatic switch device ii are accordingly actuated into circuitclosing position in engagement with their associated contact members Bio and 82a, respectively.

Associated with each of the pneumatic switch devices 2s is a pair of resistors 88 and 89 and associated with each of the pneumatic switch devices 3! is a similar pair of resistors 88 and 89. The resistors of each pair have one end thereof connected by a wire 9| to the supply wire 3, the opposite end of the resistor 88 being connected to one of the contact members Bio of the associated pneumatic switch device, and the other end of the resistor 89 being connected to one of the contact members 82a of the associated pneumatic switch device. The remaining contact members Bia and 82a of the pneumatic switch devices 29 and Si are each connected by wires 92 and 93, respectively, to the release wire 5 and to the application wire 4, respectively.

It will thus be seen that when the chamber E6 of either of the pneumatic switch devices 29 and 35 is vented to atmosphere, the supply wire connected to the application wire 4 through resistor 89 and also connected to the release wire 5 through the resistor 88.

The resistors 88 and 89 are so designed as to limit the normal or checking current flowing through the application and release wires 4 and 5 to a relatively low value which is effective to cause pick-up of the relays 22 and 23 of the signal equipments 2i and 21a, but which is insuificient to actuatively energize the electromagnets 35 and l? of the magnet valve devices l2 and 13 on the motor car and trailer cars.

The pneumatic switches 21 and 28 On the motor car are substantially similar to the pneumatic switches 29 and 3| and differ therefrom in that the piston stem 19 thereof carries in insulated relation thereon an additional pair ofv contact members 95 and $6 which are actuated out of contact with associated pairs of stationary contact members 95a and 960., respectively, when fluid under pressure is supplied to the chamber l8 thereof and which are actuated into circuitclosing relation in contact with the associated contact members 95a and 96a when fluid under pressure is vented from the chamber 15. One of the contact members 95a and one of the contact members 95a of pneumatic switch device 28 are connected by a wire 93, which is connected to the negative terminal of the battery l8, as by connection to ground at 99. The other contact members 95a and 96a of the pneumatic switch 28 are connected by wires NH and I02, respectively, to one contact member 95a and one contact member 95a of the pneumatic switch 21, respectively. The other contact members 95a and 95a, of the pneumatic switch Z'l are connected, respectively, to one end of a resistor I03 and one end of a resistor I04, respectively, the opposite ends of the resistors Hi3 and HM being connected by wires I05 and I66, respectively, to the release wire 5 and the application wired, respectively.

The chamber "H5 of the pneumatic switch device 21 is connected by a branch pipe E! to the brake pipe I at a point between the angle cock 9 and the hose coupling 8 at the head end of the motor car, while the chamber 76 of the pneumatic switch device 28 is connected by a branch pipe 108 to the brake pipe I at a point between the angle cock 9 and the flexible hose coupling 8 at the rear end of the motor car. The angle cock 9 at the head end of the motor car is in closed position in order to close the brake pipe '5 at the head end of the train while the angle cock at the rear end of the motor car is in open position normally when the motor car hauls one or more trailer cars. Consequently, the chamber 16 of the pneumatic switch device 21 is vented to atmosphere and the chamber 16 of the pneumatic switch device 23 is normally charged with fluid under pressure from the brake pipe I.

It will thus :be seen that as long as a trailer car is coupled to the motor car, the pneumatic switch device 23 will be actuated so that the contact members 95 and 36 are in circuit-opening position. However if the motor car travels alone,

without any trailer car couple-d thereto, the chamber 15 of the pneumatic switch device 28 will be vented to atmosphere the same as the chamber 16 of the pneumatic switch 21, since the angle cock 9 at the rear end of the motor car,

will be then closed and the flexible hose coupling 8 open to atmosphere.

The resistors Hi3 andlM are thus connected across or between the release Wire 5 and the application wire i, respectively, and the negative terminal of the battery I8 at the ground connection 99 only when the motor car is operating alone, the resistors Hi3 and I04 thereby serving to simulate or take the place of the electromagnets of the magnet valve devices i2 and 13 on trailer cars so as to prevent excessive current be ing supplied to the magnet valve devices l2 and i3 on the motor car by operation of the brake switch devices I9 or Mia.

The control switches 32 and 33 are provided for selectively connecting the resistors 38 and 89, associated respectively with the pneumatic switch devices 2'! and 28, between the supply wire 3 and the release and application wires 5 and 4 respectively. It will be apparent that when the motor car is operating alone without any trailer car, the normal low checking current in the train wires 4 and 5 must traverse the entire length of the motor car in order to serve as a check on the integrity of those wires. The function of the control switch 33 is, therefore, to connect the resistors 88 and $53, associated with the pneumatic switch device 26, in the circuit between the supply wire 3 and the release and application wires 5 and 4, respectively, when the motor car is being operated from the head end of the car having the brake switch device i9 and the signal equipment 2|. The control switch 32 is provided for closing the circuit connection from the supply wire 3 through the resistorsBB and 89, associated I suitable construction and are illustrated diagrammatically as comprising a movable contact segment E33 and a plurality of stationary contact members IH, H2 and H3.

The contact members HI of the control switches 32 and 33 are connected by wires H5 and H4, respectively, to the supply wire 3. The contact members H2 and H3 of the control switch 33 are connected by wires H6 and H1, respectively, to corresponding terminals of the resistors 39 and 88 respectively, associated with the pneumatic switch device 28. In a similar manner, the contact members H2 and H3 of the control switch 32 are connected by wires H8 and H9, respectively, to corresponding terminals of the resistors 89 and 88 associated with the pneumatic switch device 21.

The control switches 32 and 33 may be of individual construction adapted for manual operation but it is preferable that they be associated with some operating device on the motor car such as the reverser switch associated with the motor controller at each end of the motor car, respectively, or with the brake switch devices l9 or l9a, in order to insure the proper conditioning thereof automatically.

As is well known, only one handle is provided for operating the reverser switch associated with the motor controller at one end of the motor car and the reverser switch associated with the motor controller at the opposite end of the motor car and that upon removal of the reverser switch handle, the reverser switch is automatically conditioned in a handle-oft or neutral position. The contact member I09 of the control switches 32 and 33 may, therefore, be carried on the control drum of the reverser switch in such position that when the handle of the reverser switch is removed, the contact member I09 connects the contact members Ill, H2 and H3 and that when the reverser switch is operated either into forward or reverse position, the contact segment I09 disengages the contact members HI, H2 and I 13. Thus the control switch 32 or 33, at the end of the car opposite to that at which the operator is stationed and from which the motor car is being driven, will automatically be in the closed position, while the control switch 32 or 33 at the end of the car where the operator is stationed and from which the motor car is being operated is automatically in circuit-opening position.

Operation Assuming a train of cars including the motor car and one or more trailer cars coupled to the motor car, the equipment is charged initially by fluid under pressure from the main reservoir it carried on the motor car, fluid under pressure being supplied at a pressure as regulated by the feed valve device 15 into the brake pipe I to charge the local reservoirs H on the motor car and on the trailer cars. It will be understood that the angle cocks 9 at the head and rear end, respectively, of the train are closed, whereas the angle cocks 9 intermediate thereof are opened in order to permit the flow of fluid under pressure through the brake pipe I. As a result, the pneumatic switch device 2! at the head end of the v, 75 motor car is actuated to circuit-closing position,

since the chamber I6 thereof is vented to atmosphere, and the pneumatic switch device 3! at the rear end'of the last trailer car is likewise actuated to circuit-closing position, due to the venting of fluid under pressure from its chamber 16. The pneumatic switch devices 28 and 29, representative of all pneumatic switch devices intermediate of the pneumatic switch devices 2! and 3!, are actuated to circuit-opening position due to the supply of fluid under pressure from the brake pipe I to the chambers I6 thereof.

The pneumatic switch device 3| accordingly establishes checking circuits whereby the relays 22 and 23 of the signaling equipments 2| and 2m are energized. The circuit for energizing the relay 22 of signaling equipment 2| extends from the positive terminal of the battery l8 through a wire 6| to the supply wire 3 and thence to the last trailer car, then through wire 9| to the point 90 whence the circuit divides, one part extending through resistor 89, contact members 82 and 82a of the pneumatic switch 3|, wire 93, application wire 4 back to the motor car, and through the winding of the relay 22 and the ground connection [3 to the negative terminal of the battery N3, the other part extending from the point 90 through resistor 88, contact members 8| and Bla of the pneumatic switch device 3|, wire 92, release wire 5 back to the motor car, and thence through the winding of the relay 23 and the ground connection 53 to the negative terminal of the battery l8.

While the electromagnets of magnet valve devices 12 and I3 are connected in parallel with the relays 22 and 23, they are not operatively energized by the low checking current flowing through the circuits just traced. However, the relays 22 and 23 of the signaling equipment 2| and'also of the signaling equipment 2| 0, are energized to separate the contact members 22a and 23a thereof from the stationary contact members associated therewith.

If, therefore, with checking circuits just described established, the train wires 3, t and 5 are unbroken, the relays 22 and 23 are picked up and as a result the annunciator 24 is silent and. the signal lamp 25 is not illuminated.

Assuming a train comprising the motor car and one or more trailer cars to be traveling along the road, the equipment being conditioned as shown in Fig. 1 with the brake switch I9 in release position under the control of the operator, a service application of the brakes is initiated by the operator turning the handle 69 on the brake switch 19 to service application position wherein the contact segment 59 of the brake switch connects the contact members 62, 63 and 64. Circuits are accordingly established for energizing the application magnet valve devices l2 and the release magnet valve devices l3 on the motor car and on the trailer car. The circuits for energizing the application magnet valve devices l2 extends from the positive terminal of the battery 18 through the wires BI and 65, contact member 62, contact segment 59 and contact member 34 of the brake switch l9, wire 61, application wire 4, and thence in parallel through all of the electromagnet windings 38 of the magnet valve devices l2 to the ground connection and thus to the negative terminal of battery l8.

The circuit for energizing the release magnet valve devices l3 extends from the positive terminal of the battery l8 to the contact segment 59 of the brake switch 19 as previously traced for the magnet valve devices !2, and thence ply of fiuid under pressure from the correspond ing local reservoir ii to the associated brake cylinder it) through pipe 36, chamber ioflthe application magnet valve device it, past the un-. seated valve 3%, through chamber and pas sage and pipe ll.

trailer cars.

When a desired degree of application of the brakes is attained the operator turns the handle of the brake switch it to the lap position ct segment and connected by the contact segment 59.

The circuit previously traced, for energizing the electromagnet winding 38 of each magnet valve device it is accordingly interrupted while the circuit for energizing the electromagnet winding ll of each release magnet valve device'lia is maintained. The application valve 3% of each ar ication magnet valve device i2 is thus actut-o seated position to close off the further ated supply of fluid under pressure to the corresponding brake cylinder to and the release valve M of each release magnet valve device 53 remains in seated position to prevent the loss of fluid underpressure from the brake cylinder so that the I brake continues to be applied according :to the degree of attaining brake cylinder pressure.

If it is desired to increase the degree of braking effect, the operator returns the brake switch to lap position to hold the brakes applied ac cording to the degree of brake cylinder attained.

A full service application of the brakes is pressure effected when the pressure of each brake cylinder braking, following a service application initiated as just described, he operates the brake switch $9 from the lap position to the rel-ease position, holds it there long enough to reduce the brake cylinder pressure iii to the desired degree and then returns the handle to lap position; In the release position of the brake switch the application magnet valve devices 52 and release magnet valve devices l3 are all de-energized and:

consequently the application valves 34 are actuated to close off the supply of fluid under pressure to the reservoirs It to the brake cylinders it! while the release valves Mi are unseated to exhaust fluid under pressure from the brake cylinders through the communication established by way of pipe and passage il, branch pipe 4-9,

chamber $8, past the unseated release valve 44,

' IZI, application Wire 4, and through the winding chamber :35 and exhaust port 46.

The brakes are thus simul taneously applied on the motor car and on the 1 thereof, wherein the connection between the and contact member 66 is 1, alien and wherein only the contact members 52 When the brake switch handle 60 is returned to lap position the release magnet Valve devices 53 are again energized as previously described sothat the release valves 44 are actuated to seated position to close oiT the further exhaust of fluid under. pressure from the brake cylinders it. The brake cylinder pressure may be reduced in any number of desired steps by repeating the operation of the brake switch handle 6&3 from lap position to release position and back to lap position again.

The brakes may be fully released by operating brake switch handle 60 to release position and allowing it to remain there so that the fluid under pressure is fully exhausted from the brake cylinders t0.

Checking circuit for motor car and trailer cars If, with the equipment conditioned as shown in Fig. 1, any of the train wires 3, 4 and 5 should be broken, the circuit previously traced for either one or both of the relays 22 and 23 in the signal equipments 2| and Zla will be interrupted and thus movable contact member 2211 or 2311 drops into circuit-closing position to complete the circiL t for energizing the signal lamp 25 and the annunciatorid to indicate that there is a break in the control circuit and that the electrically controlled brake cannot be relied upon.

It will be observed that the pneumatic switch device 3i at the rear end of the last trailer car is automatically conditioned to complete the checking circuit when other trailer cars in the rear of a particular trailer car are uncoupled therefrom. It will be understood that according to customary practice, the angle cock 9 at the rear end of the last car of the train is always operated to closed position before uncoupling the flexible hose coupling 8, in order to prevent the loss of pressure in the brake pipe 7. Thus, the pneumatic switch device, exemplified by pneumatic switch-device 3|, is automatically conditioned to complete the checking circuit at the rear end of the last trailer car.

It will, therefore, be seen that without regard to the number of trailer cars and without regard to which of the trailer cars is last in the train the checking circuits are always effective.

Checking circuit for motor car alone Assuming that the motor car is traveling alone, that is without any trailer cars coupled thereto, and that the operator is stationed at the head end of the motor car at which the brake switch is and signaling equipment 2| is located, the checking circuits are maintained through the pneumatic switch device 28, which is actuated to circuit-closing position since it is the last pneumatic switch device at the rear of the brake pipe "I.

Since the operator is stationed at the end of the motor car opposite to that at which the control switch 33 is located, the control switch 33 isin circuit-closing position connecting the contact members Ill, H2 and H3. The checking circuits for maintaining the signal relays 22 and 23 energized are accordingly established. The circuit for the relay 22 of the signal equipment 2! extends from the positive terminal of the bat tery l8 through wire BI and the supply wire 3, wire H4, contact member H I switch 33, contact segment I89, contact member H2, wire H6, resistor 89, contact members 82a and'82of pneumatic switch device 28, the wire of the control of the relay 22 to the ground connection 13 and thus to the negative grounded terminal of battery l8.

The circuit for energizing the winding of the relay 23 extends from the positive terminal of the battery l8 to the contact segment I99 of the control switch 33 in the mannerjust traced for the relay 22, and thence through contact member H3, wire I ll, resistor 88, contact members Ma and 8! of the pneumatic switch, device 28, the wire [22, release wire 5 and thence through the winding of the relay 23 to the ground connection 13 and through ground to the negative terminal of battery [8.

Both relays 22 and 23 are accordingly energized by the normal low checking current which traverses the entire length of the application and release wires carried on the motor car. In the event of the train wires 3, 4 and 5 carried on the motor car being broken either one or both of the relays 22 and 23 will be deenergized and the circuit thereby completed for energizing the annunciator 24 and the signal lamp 25.

Should the operator be stationed at the rear end of the car at which the brake switch I 9a and the signaling equipment 2| a is located, as when the motor car is driven from the rear end, the control switch 32 will be in closed position conmeeting the contact members HI, H2 and H3 thereof, whereas the control switch 33 will be in open position wherein the contact members Ill, H2 and H3 thereof are disconnected.

The checking circuit for the relay 22 of signal equipment 2 la is then established from the positive terminal of the battery I 8 through wire El and supply wire 3, wire H5, contact member H I, contact segment Hi9 and contact member H2 of the control switch 32, wire H8, resistor 89 associated with the pneumatic switch device 27, contact members 82a and 82 of the pneumatic switch device 21, wire Hi5, application wire 4 and through the winding of the relay 22 to the ground connection.

The circuit for energizing the relay 23 of signal equipment'Z la extends from the positive terminal of the battery E8 to the contact segment I09 of the control switch 32 in the manner previously traced for the relay 22, and thence through the contact member H3 of the control switch 32, wire H9, resistor '88 associated with the pneumatic switch device 21, contact members 8m and 8i of the pneumatic switch device 21, wire H35, release wire 5, and through the winding of the relay 23 to the ground connection. Thus the checking current flows through the entire length of the application and release wires 4 and 5 carried on the motor car and in the event of the application or release wires becoming broken at any point along the length thereof either of the relays 22 or 23 respectively will become deenergized to complete the circuit for energizing the annunciator 24 of the signal lamp 25 of the signal equipment Zia.

It will be appreciated that due to the absence of trailer cars and the accompanying current load of the electromagnet valve devices l2 and I3 on the trailer cars, the current supplied to energize the magnet valve devices l2 and I3 on the motor car under the control of the brake switch devices is and 19a when the motor car is operating or traveling alone may be excessive and thereby tend to cause overheating and even possibly burning out the electromagnet windings of the magnet valve devices 12 and I3 on the motor car. I, therefore, provide the resistors I03 and I84 to simulate the current load effect of the magnet Valve devices l2 and I3 on the trailer cars and limit the energizing current for the magnet valve devices l2 and I3 on the motor car, supplied under the control of the brake switch devices l9 and Ilia, to a safe maximum value.

It will be seen that when the motor car is operating alone without any trailer cars coupled thereto, both the pneumatic switch device 2i and the pneumatic switch device 28 are actuated to circuit-closing position to connect the resistor I84 in parallel with the electromagnet winding. 38 of the magnet valve device l2 from the application wire 4 through the wire I06, resistor I04, contact members 96a and 96 of the pneumatic switch device 21, wire I82, contact members' 96a and 96 of the pneumatic switch device 28, wire 98 to the ground connection 99, the re sistor I03 being simultaneously connected in parallel relation with the electromagnet winding 41 of the release magnet valve device 13 from the release wire 5 through wire 15, the resistor I83, contact members a and 95 of the pneumatic switch device 21, wire I8I, contact members 95 and 95d of the pneumatic switch device 28, and wire 98 to the ground connection 99.

Summary Summarizing, it will be seen that I have provided a simple and efiective system for checking or verifying the integrity of the brake control circuits, regardless of the number of the cars in the train and without requiring any particular car to be the last car of a train. The system which I have devised is further adapted to be effective, even when the locomotive or motor car is operating or traveling alone with no trailer cars coupled thereto.

While I have shown and described only one embodiment of my invention, it will be apparent that various omissions, additions or modifications may be made in the embodiment shown, without departing from the spirit of my invention. It is not my intention therefore to limit the scope of my invention except as necessitated by the scope of the prior art.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In an electrically controlled brake system for a train of cars, in combination, a normally open brake control circuit, a normally closed checking circuit including a portion of said brake control circuit, means on each car of the train operative to complete the checking circuit, and means for so controlling said last means as to cause only the means on the last car of the train to be operated to complete the checking circuit.

2. In an electrically controlled brake system for a train of cars, in combination, a normally open brake control circuit, a normally closed checking circuit including a portion of said brake control circuit, means on each car of the train operative to complete the checking circuit, and means effective to prevent all of said last means except that on the last car of the train from being operated to complete the checking circuit.

3. In an electrically controlled brake system for a train of cars, .in combination, a normally open brake control circuit, a normally closed checking circuit including a portion of said brake control circuit, means on each car of the train operative to complete the checking circuit,

and fluid pressure responsive means for controlling said last means.

4. In an electrically controlled brake system for a train of cars, in combination, a brake pipe normally charged with fluid under pressure,- a normally open brake control circuit, a normally closed checking circuit including a portion of said brake control circuit, means on each car of the train operative to complete the checking,

circuit, and means controlled by brake pipe pressure and effective upon the separation of a caring circuit including said train wires, means on each car operative to complete the checking circuit, and means controlled by brake pipe .pressure for so controlling said last means-as to cause only the means on the last car to be opi4 erated to complete the checking circuit.

6. In an electrically controlled system for a train of cars, in combination, a normally open brake control circuit, a normally closed checking circuit including a portion of said brake control circuit, means on each car operative to complete the checking circuit, a control pipe extending throughout the train and adapted to be .sectionalized into different portions, and fluid pressure responsive means controlled according to the pressure in the various sectionalized portions of the control pipe for controlling the operation of said last means.

7. In an electrically controlled brake system for a train of cars, in combination, a normally open brake control circuit, a normally closed checking circuit including a portion of said brake control circuit, means on each car operative to complete the checking circuit, a control pipe extending throughout the train, a portion of which is normally charged with fluid under pressure and another portion from which fluid under pressure is normally discharged, and means responsive to the pressure in the said portions of the control pipe for causing only the means on the last carto be operated to complete the checking circuit.

8. In an electrically controlled brake system for a train of cars, a normally open brake control circuit, a normally closed checking circuit including a portion of the brake control circuit, a control pipe extending through the length of the train and normally charged with fluid under pressure, means on each car for segregating the end portion of the section of the control pipe carried on the car from the charged portion, the pressure in the segregated end portion on each car being reduced only when the segregated end portion is at the rear end of the control pipe, and fluid pressure responsive means on each car effective only when the end portion of the section of the control pipe on the car is segregated and the pressure therein reduced for completing the checking circuit.

9. In an electrically controlled brake system for a car or train of cars, in combination, a normally open brake control circuit including electroresponsive means eflective only in response to a certain minimum current in said circuit to effect application of the brakes, a normally closed circuit including a portion of the normally open circuit and having a normal checking current therein which is less than said certain minimum current, means on each car adapted to limit the current in the normally closed checking circuit to less than said certain minimum current, and switch means on each car effective to complete the checking circuit and render the current limiting means thereon effective.

10. In an electrically controlled brake system for a car or train of cars, in combination, 2. normally open brake control circuit including elecroresponsive means effective only in response to a certain minimum current in said circuit to effect application of the brakes, a normally closed circuit including a portion of the normally open cir-' cuit and'having a normal checking current there in which is less than said certain minimum current, resistance means on each car adapted to limit the current in the normally closed checking circuit to less than the said certain minimum current, and switch means on each car effective to complete the checking circuit through the resistance means thereon.

11. In an electrically controlled brake system for a train of cars, in combination, a brake pipe extending throughout the train and normally charged with fluid under pressure, a normally open brake control circuit including a plurality of rain wires, a normally closed checking circuit including said train wires, and separate switch means at opposite ends of each car operative to circuit-closing position to connect one of said train wires to the other train wires to complete the checking circuit, and fluid pressure responsive means for each switch means normally subject to the pressure in the brake pipe for maintaining the switch means in circuit-opening position and responsive to the reduction in pressure in the end section of the brake pipe when a car is uncoupled at the end of the train for operating the switch means.

12. In .an electrically controlled brake for a car, in combination, a normally open brake control circuit including a plurality of train wires extending the length of the car, a normally closed checking circuit including said train wires, a plurality of signal means operating on said checking circuit and connected respectively to opposite ends of certain of the train wires, and switch means at opposite ends of the car adapted to connect one of the train wires to the said certain trainwires to complete the checking circuit for the signal means at the opposite end of the car through the entire length of the certain train wires.

13. In an electrically controlled brake for a car, in combination, a normally open brake control circuit including a plurality of train wires extending the length of the car, a normally closed checking circuit including said train wires, a plurality of signal means operating onsaid checking circuit and connected respectively to opposite endsof certain of the train wires, switch means at opposite ends. of the car adapted to connect one of the train wires to the said certain train wires to complete the checking circuit for the signal means at the opposite end of the car through the entire length of the certain train wires, and means for preventing the connection by said switch means of said one train wire to the other train wires at one end of the car unless the car operator controls the motion of the car from the opposite end of the car.

14. In an electrically controlled brake system for a motor car adapted to travel alone or with one or more trailer cars coupled thereto, in combination a normally open brake control circuit, electroresponsive means on the motor car operating on said circuit for controlling application and release of the brakes, and means effective only when the motor car travels alone for limiting the current supplied to the electroresponsive means.

15. In an electrically controlled brake system for a motor car adapted to travel alone or with one or more trailer cars coupled thereto, in combination a normally open brake control circuit, electroresponsive means on the motor car operating on said circuit for controlling application and release of the brakes, means adapted to limit the current supplied to the electroresponsive means, and means on the motor car effective only when the motor car travels alone for rendering the current limiting means effective.

16. In an electrically controlled brake system for a motor car adapted to travel alone or with one or more trailer cars coupled thereto, in combination a normally open brake control circuit, electroresponsive means on the motor car operating on said circuit for controlling application and. release of the brakes, resistance means on the motor car adapted to be connected in said brake control circuit to limit the current supplied to the:

electroresponsive means, and switch means efiec tive to connect said. resistance means in said. brake control circuit only when the motor car travels alone.

17. In an electropneumatic brake system for a motor car adapted to travel aloneor with one ormore trailer cars coupled thereto, in combination, a normally open brake control circuit for con-- trolling application and release of the brakes on the motor car and on the trailer cars, a control pipe normally charged with'fluid under pressure, and comprising separate sections on the motor car and on the trailer cars, the successive sections being connected when the cars having the sections are coupled, means for segregating the opposite end portions of the control pipe section on each car from the central portion of the section, the opposite end portions being vented to atmosphere when no other car is coupled to that end of the car having the control pipe section, means on the motor car for limiting the current in the brake control circuit, and two fluid pressure responsive means operatively responsive to the pressure in the one end portion and in the opposite end portion respectively of the control pipe section on the motor car and effective jointly only when the motor car has no cars coupled thereto for rendering the current limiting means effective.

18. In an electrically controlled brake system for a motor car adapted to travel alone or with one or more trailer cars coupled thereto, the combination including a brake control circuit, electroresponsive means on the motor car operating on said circuit for controlling application and re-- lease of the brakes, means effective to prevent energization of the said electroresponsive means to an abnormally high degree, and means effective only when the motor car travels alone for rendering said last means effective.

JOSEPH C. MCCUNE. 

